FeynCalc manual (development version)

 

Uncontract

Uncontract[exp, q1, q2, ...] uncontracts Eps and DiracGamma.

Uncontract[exp, q1, q2, Pair -> {p}] uncontracts also p \cdot q_1 and p \cdot q_2;

The option Pair -> All uncontracts all momenta except OPEDelta.

See also

Overview, Contract.

Examples

LC[\[Mu], \[Nu]][p, q] 
 
Uncontract[%, p]

\bar{\epsilon }^{\mu \nu \overline{p}\overline{q}}

\overline{p}^{\text{\$AL}(\text{\$19})} \bar{\epsilon }^{\mu \nu \;\text{\$AL}(\text{\$19})\overline{q}}

GS[p] 
 
Uncontract[%, p]

\bar{\gamma }\cdot \overline{p}

\bar{\gamma }^{\text{\$AL}(\text{\$20})} \overline{p}^{\text{\$AL}(\text{\$20})}

Uncontract[LC[\[Mu], \[Nu]][p, q], p, q]

\overline{p}^{\text{\$AL}(\text{\$22})} \overline{q}^{\text{\$AL}(\text{\$21})} \left(-\bar{\epsilon }^{\mu \nu \;\text{\$AL}(\text{\$21})\text{\$AL}(\text{\$22})}\right)

By default scalar products are not uncontracted.

Uncontract[SP[p, q], q]

\overline{p}\cdot \overline{q}

Use the option Pair->All to make the function take care of the scalar products as well

Uncontract[SP[p, q], q, Pair -> All]

\overline{p}^{\text{\$AL}(\text{\$23})} \overline{q}^{\text{\$AL}(\text{\$23})}

Uncontract[SP[p, q]^2, q, Pair -> All]

\overline{p}^{\text{\$AL}(\text{\$24})} \overline{p}^{\text{\$AL}(\text{\$25})} \overline{q}^{\text{\$AL}(\text{\$24})} \overline{q}^{\text{\$AL}(\text{\$25})}

For Cartesian scalar products you need to use the option CartesianPair->All

Uncontract[CSP[p, q], q, Pair -> All]

\overline{p}\cdot \overline{q}

Uncontract[CSP[p, q], q, CartesianPair -> All]

\overline{p}^{\text{\$AL}(\text{\$26})} \overline{q}^{\text{\$AL}(\text{\$26})}